TL;DR
An Abbott Freestyle Libre continuous glucose monitor (CGM) bug falsely reported dangerously low glucose levels, and the U.S. FDA says the issue injured more than 700 people and was linked to seven deaths. The blog author says they received a pharmacy notice, cross-checked lot numbers, and had recently used an affected device; the technical cause and scope remain vague.
What happened
A December blog post by Bradley M. Kühn reports that an undisclosed fault in Abbott's Freestyle Libre continuous glucose monitors led to falsely reported extreme low glucose readings. The U.S. Food and Drug Administration, cited in the post, attributes more than 700 injuries and seven deaths to this malfunction. The author received an alert from a pharmacy on December 3, 2025, checked lot numbers on saved packaging, and found that he had recently worn an affected device. The false low readings can prompt users to consume sugar to counter perceived hypoglycemia; if the reading is incorrect, that intervention can itself be dangerous. The post criticizes the lack of technical detail from Abbott and regulators, notes uncertainty about whether the root cause is hardware or software, and points to broader debates about proprietary medical-device ecosystems versus community review and open-source approaches.
Why it matters
- False low glucose readings can lead patients to take immediate corrective action that may harm or kill them if the measurement is incorrect.
- The FDA reported more than 700 injuries and seven deaths connected to the malfunction, indicating a widespread safety problem.
- Opaque disclosures from the manufacturer and regulators prevent independent technical review and make it harder for outside experts to confirm causes and fixes.
- Proprietary device software and restrictive licensing or indemnity terms may limit patients’ ability to pursue remedies or enable third-party auditing.
Key facts
- The U.S. FDA announcement cited in the post links the Freestyle Libre issue to over 700 injuries and seven deaths.
- The malfunction caused devices to report an erroneously very low glucose level.
- The author received a pharmacy text on 2025-12-03 and cross-checked lot numbers on saved CGM packaging, concluding he had recently worn an impacted device.
- The specific technical cause — whether a hardware defect, software bug, or other factor — is described as unclear and the disclosure by the manufacturer was characterized as vague.
- The author references community-developed free and open-source software (Juggluco) that has reverse-engineered activation and data protocols for some CGMs.
- The post recalls historical incidents where medical-device software failures harmed patients (Therac-25 in 1985 and unsupported ocular implants in 2020) to situate the current event.
- The author reports at least one discrepancy between Abbott’s webform and the FDA spreadsheet when cross-referencing lot and serial numbers.
What to watch next
- Updated, detailed technical findings from Abbott or the FDA that clarify whether the root cause was software, hardware, or a supply/lot issue — not confirmed in the source.
- Whether independent researchers, NGOs, or open-source communities will be allowed to inspect affected devices for reproducible analysis — not confirmed in the source.
- Any legal actions or class lawsuits against Abbott and whether contractual terms or indemnities affect patients’ ability to pursue claims — not confirmed in the source.
Quick glossary
- Continuous Glucose Monitor (CGM): A wearable device that measures glucose levels in real time and provides readings to help manage diabetes.
- FDA (U.S. Food and Drug Administration): The U.S. federal agency that regulates medical devices, drugs, and other health-related products.
- Proprietary software: Software owned and controlled by a company, typically distributed under restrictive licensing that limits access to source code.
- FOSS (Free and Open-Source Software): Software licensed to permit users to run, study, modify, and share the code, allowing public review and contributions.
- False low reading: A sensor or device output that incorrectly indicates a dangerously low glucose level when actual blood glucose is not low.
Reader FAQ
How many deaths were linked to the CGM bug?
The post cites an FDA announcement that links seven deaths to the device malfunction.
Which product was affected?
The blog refers to Abbott's Freestyle Libre series, naming Freestyle Libre Plus in the narrative.
Was the bug caused by hardware or software?
Not confirmed in the source; the author states the disclosure is vague and the root cause remains unclear.
Did the author personally use an affected device?
The author says they cross-checked lot numbers from saved packaging and had recently worn an impacted monitor.
Are lawsuits or recalls underway?
Not confirmed in the source; the author expresses hope for class-action litigation but notes potential contractual hurdles.
Home / News / Blog Seven Diabetes Patients Die Due to Undisclosed Bug in Abbott's Continuous Glucose Monitors by Bradley M. Kühn on December 23, 2025 I wrote last month…
Sources
- Seven Diabetes Patients Die Due to Undisclosed Bug in Abbott's Glucose Monitors
- Glucose Monitor Sensor Issue from Abbott Diabetes Care
- 7 deaths, hundreds of injuries linked to faulty Abbott …
- Faulty glucose monitors linked to 7 deaths and more than 700 …
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